1. Field of the Invention
The invention is directed to a method and apparatus for heating volumes of media in a closed receptacle by means of an electromagnetic radiation.
2. Discussion of Background Information
In medical applications and therapeutic procedures, it is often necessary to provide a patient with a permanent access. The patient can then receive solutions with medication or other contents, as needed, via this access.
A typical application is for dialysis patients who must occasionally be connected to a dialysis machine. In this regard, it is possible to provide a coupling device at the permanent access remaining on the patient so that the access can be connected to a dialysis machine.
Of course, it is extremely important that the risk of infecting the patient be eliminated as far as possible when reconnecting the coupling device.
A method for disinfecting coupling devices of this type is described in a publication by Fessia et al. (1990, Moist heat intraluminal disinfection of CAPD connectors, Perit.Dial.Bull. 6: 164-168). The coupling devices usually comprise two parts having connection areas that correspond to one another. This system is also known as a Luer® Lock or Luer® connector (ISO 594-1: 1986; EN 20594-1:1993; DIN EN 20594-1:1996). In closed condition, the coupling device has an interior space through which, e.g., the dialysis solution flows. In order to disinfect the coupling device before a treatment, this coupling device is filled with the dialysis solution (hereinafter referred to as medium) and the infusion line and diffusion line for the dialysis solution are closed. Subsequently, the coupling device is irradiated by microwave radiation until the medium reaches a temperature of at least 100° C. The irradiation period specified by Fessia et al. is 54 seconds. It was possible by means of this method to reduce the 106 microorganisms tested (gram positive and gram negative bacteria, yeasts and mold) to the point where the disinfection requirements (bacterial count reduced by at least a factor of 105) were met.
Grabowy et al. (1998, New connection method for isolating and disinfecting intraluminal path during peritoneal dialysis solution-exchange procedures, Adv.Perit.Dial. 14:149-154) describe a coupling device for a dialysis machine having infusion line and diffusion line closed in a pressure-tight manner and the medium is heated by microwave radiation. The medium is heated from 25° C. to temperatures of greater than 100° C. within about 10 seconds, which is made possible by the pressure-tight closure. The closure further prevents escape of potentially contaminated parts of the medium and ensures that all of the potentially contaminated medium is subjected to heating. The coupling device which may be conceived of as a receptacle is made of plastic that is substantially transparent (transmissive) to microwave radiation.
Equipment capable of heating and disinfecting receptacles can be operated by means of the methods described above. This is comparatively unproblematic when the shape, dimensions, material, etc. of the receptacles and media are known. However, the composition of plastics may vary between different batches or from one supplier to another. Receptacles from different suppliers may also be composed of different materials. But in order to guarantee safe heating of the entire medium, the influences of materials on the heating process and possibly different configurations of the receptacles must be taken into account.
Thus medical personnel are faced with the substantial problem of knowing or finding out what material the receptacle currently in use is made of.
It is the object of the invention to suggest an improved method for heating volumes of media in a closed receptacle by means of an electromagnetic radiation, which method can be used for a variety of receptacles having different thermodynamic characteristics. The invention has the further object of suggesting an apparatus for implementing the method.